Fix circularity detection for AST-based type inference in the presence of closures.

pkg/analyzer/test/src/task/strong/inferred_type_test.dart

Index: pkg/analyzer/test/src/task/strong/inferred_type_test.dart
diff --git a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
index a6867401c46e215cccf90efd503112723a0e5bcb..45e0ada2bb86505783aa9b49f400845c1c2493d0 100644
--- a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
+++ b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
@@ -479,6 +479,32 @@ test1() {
 ''');
   }
 
+  void test_circularReference_viaClosures() {
+    var mainUnit = checkFile('''
+var x = () => y;
+var y = () => x;
+''');
+    var x = mainUnit.topLevelVariables[0];
+    var y = mainUnit.topLevelVariables[1];
+    expect(x.name, 'x');
+    expect(y.name, 'y');
+    expect(x.type.toString(), 'dynamic');
+    expect(y.type.toString(), 'dynamic');
+  }
+
+  void test_circularReference_viaClosures_initializerTypes() {
+    var mainUnit = checkFile('''
+var x = () => y;
+var y = () => x;
+''');
+    var x = mainUnit.topLevelVariables[0];
+    var y = mainUnit.topLevelVariables[1];
+    expect(x.name, 'x');
+    expect(y.name, 'y');
+    expect(x.initializer.returnType.toString(), '() → dynamic');
+    expect(y.initializer.returnType.toString(), '() → dynamic');
+  }
+
   void test_conflictsCanHappen() {
     checkFile('''
 class I1 {
@@ -2551,25 +2577,24 @@ final x = <String, F<int>>{};
     expect(x.type.toString(), 'Map<String, () → int>');
   }
 
-  void test_inferredType_opAssignToProperty_prefixedIdentifier() {
+  void test_inferredType_opAssignToProperty() {
     var mainUnit = checkFile('''
 class C {
   num n;
 }
-C c;
-var x = (c.n *= null);
+C f() => null;
+var x = (f().n *= null);
 ''');
-    var x = mainUnit.topLevelVariables[1];
+    var x = mainUnit.topLevelVariables[0];
     expect(x.name, 'x');
     expect(x.type.toString(), 'num');
   }
 
-  void test_inferredType_opAssignToProperty_prefixedIdentifier_viaInterface() {
+  void test_inferredType_opAssignToProperty_prefixedIdentifier() {
     var mainUnit = checkFile('''
-class I {
+class C {
   num n;
 }
-abstract class C implements I {}
 C c;
 var x = (c.n *= null);
 ''');
@@ -2578,15 +2603,16 @@ var x = (c.n *= null);
     expect(x.type.toString(), 'num');
   }
 
-  void test_inferredType_opAssignToProperty() {
+  void test_inferredType_opAssignToProperty_prefixedIdentifier_viaInterface() {
     var mainUnit = checkFile('''
-class C {
+class I {
   num n;
 }
-C f() => null;
-var x = (f().n *= null);
+abstract class C implements I {}
+C c;
+var x = (c.n *= null);
 ''');
-    var x = mainUnit.topLevelVariables[0];
+    var x = mainUnit.topLevelVariables[1];
     expect(x.name, 'x');
     expect(x.type.toString(), 'num');
   }